1. Field of the Invention
The present invention relates to a seal construction for electrical parts such as switches, and more particularly to a seal construction for an electric part of the type in which after having been brazed to a substrate, the parts together with the substrate are cleaned.
2. Description of the Prior Art
For example, in the case where a dual inline package switch hereinafter referred to DIP switch) is actually mounted on a substrate, normally, terminals provided on the DIP switch are soldered onto the substrate, after which they are cleaned to remove flux used during soldering. To effect such a cleaning together with the substrate, it is necessary that the DIP switch is of a closed construction. The seal construction therefor so far known is shown in FIGS. 4 and 5.
In these figures, a box-type casing 1, which is formed of a synthetic resin, is provided at opposite sides thereof with plural pairs of terminals disposed at predetermined intervals, each pair of terminals 2 being formed of electrically conductive material, the terminals 2 forming contacts for the switch interiorly of the casing 1. On the casing 1 is internally placed a panel 4 formed of a synthetic resin or metal, the panel 4 and the casing 1 constituting a switch shell or a casing. Within a cavity A interiorly of the casings 1 and 4 is movably encased plural sets of slides 3 and movable contacts 3b. Lugs 3a protruding from the upper portion of the slides 3 are exposed from a plurality of holes 4a. respectively, bored in the panel 4. Further, a sealing tape 5 is adhered to the upper surface of the panel 4 so as to block the holes 4a, and a lug portion 5a projecting from the panel is formed on one end of the tape. As shown in FIG. 6, this tape 5 is formed by adhering a narrow mask film 8 to one end of a lengthy base film 7 coated with an adhesive 6 on the whole area of the lower surface thereof, and thereafter punching it into a rectangular form in a position indicated by dash-dotted contour lines. Only the base film 7 is adhered to the panel 4 by the adhesive 6, and the lug portion 5a comprises a laminate in which the base film 7 and the mask film 8 are integrated through the adhesive 6.
In the case where the DIP switch of the closed construction is actually mounted on a substrate not shown, flux is coated in a state wherein each terminal 2 is inserted into a through-hole of the substrate, and each terminal 2 and a pattern of the substrate are fixed by soldering. If the flux is left after soldering, the pattern becomes easily corroded. Therefor, the flux may be removed by cleaning such as washing with water after completion of soldering. At that time, since the DIP switch is formed into a closed construction by the tape 5 applied to the upper surface of the casing, cleaning liquids are not entered into the cavity A during cleaning, whereby the soldered DIP switch may be cleaned together with the substrate. After the DIP switch has been mounted on the substrate in a manner as described, the lug portion 5a of the tape 5 projecting from the panel 4, i.e., a portion having no adhesion where the base film 7 and the mask film 8 are stacked one over another is picked up by fingers, whereby the tape for seal is peeled away from the panel 4. Thereafter, the lug 3a exposed onto the panel 4 is slidably moved to select a contact state between the movable contact 3b and the terminal 2 thereby obtained is a circuit as desired.
Incidentally, the mounting of a DIP switch to a substrate is normally automatically carried out by use of a device called an insertion machine for the purpose of labor-saving. This insertion machine inserts terminals 2 of DIP switch supplied int desired throughholes of a substrate. Since DIP switches are successively supplied to the insert machine, the DIP switches are housed into a magazine and are transported.
FIG. 7 is a perspective view showing one example of a magazine of this kind. Within a transparent magazine 9 made of synthetic resin is housed and disposed a plurality of DlP switches of the closed construction as described above in the lengthwise direction of the magazine. This magazine 9 has a generally A-shape, and a bottom surface 9a formed to be projected toward the upper surface extends in a longitudinal direction so that DIP switch is encased in such a manner that each of the terminals 2 may straddle on the bottom surface 9a. To mount the DIP switch housed in the magazine 9 on the substrate, the magazine 9 is made to be inclined through a predetermined angle, whereby the DIP switch is transported by utilizing its own weight thereof, thus successively supplying them to the insert machine. More specifically, by inclining the magazine 9, the DIP switches may be slidably glided on the bottom surface 9a and therefore, the lowermost DIP switch positioned in the open end of the magazine 9 is first caught by the insert machine, and the thus caught DIP switch is arranged in position on the substrate.
However, the above-mentioned conventional DIP switch of the closed construction has a difficulty in that as may be best shown in FIG. 8 which is an enlarged view of the part A of FIG. 7 the adhesives 6a forced out of the tapes 5 of the adjoining DIP switches stick each other to make it impossible to mount the DIP switches on the substrate one by one. This results from the fact that when the tape 5 is punched, the adhesive 6 is forced out of a cutting line by a punching blade. In the conventional tape 5 cut into a rectangular shape, the adhesive 6a forced out of the end of the lug portion 5a becomes stucked with the adhesive 6a forced out of the end of the tape 5 next to the former through a tape width with a relatively high adhesion.
Such an inconvenience is not limited to the case where the DIP switches are transported by the magazine 9 but similarly occurs also in case of the transporting by a part feeder.